[DFTB-Plus-User] point charges

[Bhatt, Mahesh]

Dear Dr. Balint,

Thank you for your response. I would like to calculate the PDOS of three layers of pentacene by varying these point charges. I am using this system first time, so please could you suggest me the x, y, and z coordinates of the two point charges suitable for my system of 216 atoms. How can we put these coordinates? The distance 1.4 A of one of the H atoms is total distance or any of x or y or z-distance.

Please give me some hints.

Sincerely
Mahesh
________________________________________
From: dftb-plus-user-bounces at dftb-plus.info [dftb-plus-user-bounces at dftb-plus.info] on behalf of Bálint Aradi [balint.aradi at bccms.uni-bremen.de]
Sent: Friday, May 24, 2013 1:21 PM
To: User list for DFTB+ related questions
Subject: Re: [DFTB-Plus-User] point charges

On 05/24/2013 02:52 PM, Bhatt, Mahesh wrote:
> Hi,
> Could anyone tell me whether the set of point charge given in manual of DFTB+ (I put below) making an electric dipole, which imposes an external electric field is suitable for all systems ( I mean by different types of systems and their sizes)?

You are putting a lot of unscreened external charges quite close to your
system (one of the H atoms is only 1.4 A apart from one of your
charges). You should put them farther away, depending of course, what
you are planning to do.

  Best regards,

  Bálint

--
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b_aradi/